Ask HN: Do you pay interest on your kid's piggybank?

I've been toying with the idea of explaining savings and interest rates to my kid. Currently, she just accrues money in a jar, so she's basically incentivized to spend it as soon as she gets it. The only point in saving a bit more is to buy a more expensive toy.

I see banks like Capital One have a kids savings account (1% APY), but I think this is going to be too virtual, it's going to make it look like the money just disappears and the interest rates are never going to materialize in a meaningful way.

So I'm thinking of an alternative, like at the beginning of every month give 10% of what is in the piggybank (typically a couple $). This would make it very concrete that it makes sense to save and not just spend. Although I also don't want to give unrealistic expectations about real life savings and disincentivize working for money.